The long-term objective of the proposed research is to provide an increased understanding of the functions and organization of the afferent (sensory) innervation of female reproductive organs under normal and pathological conditions, with an emphasis on the neural mechanisms underlying pelvic pain. Using the rat as a model, parallel behavioral, electrophysiological and neuroanatomical studies are proposed. Behavioral studies will determine quantitatively the levels of mechanical stimulation of the uterus and vagina that the rat detects or finds aversive. Electro-physiological studies will examine the response properties of fibers in the pelvic and hypogastric nerves to these stimuli. Neuroanatomical studies wi)l use multiple tracing methods to characterize the topographic organization of inputs to the spinal cord arising from different components of each of the pelvic structures, with an emphasis on those from reproductive organs. Most studies will focus on the healthy rat, examining and comparing changes in behavioral and electrophysiological responses that occur as a function of estrous state, pregnancy and various experimentally-induced hormonal conditions. Additional similar studies will be carried out on a rat model for endometriosis and the results compared with those obtained from healthy rats. It is reasoned that improving knowledge of the relationship between the characteristics of afferent fibers supplying female reproductive organs and the sensory consequences of their stimulation under healthy and pathological conditions will not only improve understanding of basic mechanisms underlying the reproductive process, but also lead to improved strategies for treatment of disorders of the reproductive system, in particular for treatment of the pain that is a common component of such disorders.